DID I TEAR MY ACL?
How can I determine if my ACL is torn?
Many techniques exist today to determine if the anterior cruciate ligament (ACL) is torn or just slightly injured. However, in both cases, it is important to treat these injuries using the appropriate rehabilitation program following the diagnosis in order to assure knee stability. Usually, assessment of the ACL is done by using an arthrometer, a physical examination performed by a medical practitioner or by running an MRI scan.
Arthrometer/Laximeter
Using an arthrometer is today the most efficient technique for anterior cruciate ligament (ACL) diagnosis. In the beginning, arthrometers would only be used for study purposes. However, with technology advancing at an accelerated rate since the end 20th century/beginning of the 21st century, these medical devices are now much more used for clinical purposes as they provide valuable information on knee stability.
Arthrometers run tests on the ACL using the same method as the one applied during a physical examination but instead offer better diagnostic, as the results are objective. The KT-1000 was one of the first arthrometer ever created. Its technology is based on the Lachman test, which is a physical examination test where the medical practitioner holds the femur in position while pulling the tibia towards him. When the KT-1000 would register a displacement superior to 3mm at a 134N force applied on the tibia, it would emit a sound meaning the ACL is torn. However, this device quickly showed its limitations especially in terms of test reproducibility, precision and it did not evaluate knee stability because it only evaluated the ACL at a 134N force on the tibia, hence Genourob created its own arthrometer, the GNRB.
The GNRB is the first automated anterior drawer test arthrometer. It the first device showing capabilities of evaluating knee stability as it studies the displacement of the tibia while applying different forces to recreate the anterior drawer test in order to study the compliance curves (=opposite of stiffness curves) of the anterior cruciate ligament. This analysis gives a precise result on whether the ACL is torn or not.
Physical examination
This technique is perhaps the simplest one applied by the orthopaedic community but not necessarily the most efficient one. Usually, doctors or physiotherapists do the physical examinations. Both of them check all the structures of the injured knee by performing tests such as the Lachman test, the drawer test, the jerk test etc. Comparing the behaviour of both the injured knee and the healthy knee allows the diagnosis of the anterior cruciate ligament.
While clinical physical manoeuvres are essential, they often rely on subjective factors such as clinician experience, muscle relaxation, and inherent knee variability. Currently, it is the first method applied in the process of diagnosing a torn ACL but with the results not being objective, it is well advised to fall back on more advanced techniques such as arthrometry / laximetry or doing a MRI scan.
Magnetic resonance imaging (MRI) scan
This technique allows the creation of images of soft tissues like the anterior cruciate ligament. However, blood surrounding the ACL can make it difficult to evaluate if it is torn. Besides, tests that are done with this device are also static as the patient lies still while the examination takes place making objective knee stability assessment not possible.